Known apparatus for providing information on at least one muscle in a patient comprises signal providing means for providing measurement-enabling signals for the muscle, contact electrodes for enabling the measurement-enabling signals from the signal providing means to be received by the patient, and measurement means for measuring a parameter of the muscle. The known apparatus is used for giving an indication of joint articulation, for example ankle articulation. A problem with the known apparatus is that it is difficult to position the contact electrodes precisely on the required part of the patient. Variations in positioning of plus or minus 5 mm from an optimum position may adversely affect measurement results.